Ts. Adyasuren
Ministry of Nature and the Environment, Ulaanbaatar, Mongolia

1. DESCRIPTION OF THE DATA SET

The Mongolian data set consists of 44 stations for the period 1964-2002.
Twenty-eight sites have pasture vegetation and sixteen have wheat. All the
observations were taken using the gravimetric technique for each 10-cm layer
down to a depth of 1 m, with the first layer divided into two 5-cm layers. The
data are volumetric plant-available soil moisture. Soil moisture was observed three times a month, on the
8th, 18th and 28th of the month from April through the end of October.
The data set is described in
Robock
et al. (2000). The data were used by Entin
et al. (2000) to study the scales of soil moisture variations. Observations
at some stations began as early as 1964. A majority of them began observations
during 1970. Time series data corresponding to each individual
layer are available for downloading in both GrADS and ASCII formats.

Please note that the current data set includes corrections to our previous
data, such as station locations and various formatting errors. Latitudes
and longitudes are now correct (correcting a confusion between decimals and
degrees/minutes). 11 of the
previously released 42 stations (numbered from 17 to 27) had a mixed formatting problem,
which has now been corrected.
In order to keep the data format
consistent, the first two layers (0- to 5-cm and 5- to 10-cm) are combined and
reported as a single 0- to 10- cm layer. Please use this data set for future analyses and discard
previous versions.

2. DATA PROCESS PROCEDURE

To produce plant-available soil moisture, wilting levels were
subtracted
from total soil moisture. In case the wilting levels are not available
for some stations , we used the mean value of the minimum 3 as
substitutions. This method produced homogenous soil moisture for those
Mongolian stations without measured wilting levels. By examining the
plant-available data, it seemed
to us that the wrong wilting level may have been used, as even during
dry
periods the plant-available soil moisture was still quite high.
Therefore,
we have subtracted the apparent excess from the data for some of our
analyses.

3. DATA FORMATS

Mongolian data sets are available in both ASCII and BINARY formats. Some GrADS scripts are also prepared to display time series.
Please contact us to work with them